The design of Web applications traditionally relies heavily on the navigation design. The Web as it evolves now brings additional design concerns, such as omni-presence, device-dependence, privacy, accessibility, localization etc. Many of these additional design concerns are occurrences of context-dependency, and they are typically realized by transformations of the application design that embed adaptation in the navigation. Here we focus on how to extend an application design with new functionality without having to redesign the entire application. If we can easily add functionality, we can separate additional design concerns and describe them independently from each other. By applying principles from Aspect-Oriented Programming to Web design, we can support this separation of concerns. Using a component-based implementation we show how we obtained aspect-orientation in extending Web application designs for additional design concerns.